params: remove unresponsive bootnodes

[github-actions[bot]]

These bootnodes did not respond to ./build/bin/devp2p discv4 ping requests.

For details: https://github.com/etclabscore/core-geth/actions/runs/3202643161.

[ziogaschr]

I suggest adding at least one working bootnode for each network and remove the ones suggested. I think @diega can suggest some Besu bootnodes

[meowsbits]

Closing this since #583 was merged. Let's see if the robots reopen.